X-ray structure of a new crystal form of pike 4.10 β parvalbumin

A new crystal form of pike (pI 4.10) parvalbumin has been crystallized in presence of EDTA at pH 8.0. The crystals are orthorhombic, space group P2₁2₁2₁, with a = 51.84, b = 49.95, c = 34.96 Å. Diffractometer data were collected to 1.75 Å. The structure was solved by molecular replacement and refined to R = 0.168 for 7774 observed reflections [I≥ 2σ(I)] in the range 8.0–1.75 Å. In spite of the presence of EDTA, calcium ions are present in both primary binding sites. As compared to the previously reported structures, the main differences concern the conformation of the N-terminal residues and the packing in the unit cell.